Ball roller bearings are rolling contact bearings with special rolling elements designed as ball rollers, which, starting from a basic ball shape, each have two side faces, which are formed as flats on said basic ball shape, which are arranged parallel to one another and between which the running surfaces of the ball rollers are in each case arranged. Ball roller bearings of this kind are widely known in many different versions in the form of single-row, two-row, three-row or even four-row radial or angular contact ball roller bearings and, owing to the special shape of the rolling elements, they also require special cage designs in order, on the one hand, to limit a maximum angular position of the ball rollers relative to the longitudinal axis of the bearing and, on the other hand, to avoid wobbling of the ball rollers transversely to the direction of revolution thereof.
A single-row ball roller bearing of the type in question is already known, for example, from the German patent application with the official file reference 10 2008 016 977.3, which had not yet been published on the filing date of the present patent application, and essentially comprises an outer bearing ring, an inner bearing ring and a multiplicity of ball rollers arranged between said bearing rings. The ball rollers roll on the running surfaces thereof in two groove-shaped races machined into the inner side of the outer bearing ring and into the outer side of the inner bearing ring and are held at uniform distances from one another in the circumferential direction by a bearing cage. This bearing cage is expediently designed as a window cage, which has two lateral angular flanges of identical diameter, a plurality of pocket webs which connect said angular flanges to one another, and a plurality of cage pockets which are separated from one another by said pocket webs and, in each case, have a capstan shape which is formed from a free contour which is arranged transversely with respect to the circumferential direction for inserting a ball roller into the bearing cage and from a cross-sectional contour of a ball roller; the cross-sectional contour is integrated in the former and is arranged longitudinally with respect to the circumferential direction. The free contour of the cage pockets, which is arranged transversely to the circumferential direction, corresponds to the shape of a section plane arranged directly on the transverse axis of a ball roller while the cross-sectional contour of the cage pockets, which is arranged longitudinally with respect to the circumferential direction, has the shape of a section plane arranged above the transverse axis of a ball roller, with the result that the side edges of the pocket webs are configured with the radii of the arcuate guide faces for the ball rollers, and the guide faces correspond to running surfaces of two adjacent ball rollers. To produce a bearing cage of this kind, use is generally made of a sheet-metal strip, which is finished by profiling the angular flanges, punching the cage pockets, cutting to length to give the dimension of the circumference, rolling into a ring and welding the ends of the ring.
It has been found in practice, however, that the production of the bearing cage in the form described is subject to special technical problems, and furthermore the function of the bearing cage does not fully meet the specified requirements in terms of quality. It has thus been determined that the high filling ratio of the ball roller bearing and the associated high number of cage pockets in the bearing cage necessarily lead to it being possible for the pocket webs which separate the cage pockets from one another to be of only very narrow configuration and to said pocket webs therefore having only a low axial flexural stiffness. As a result, during the flanging of the lateral angular flanges which concludes the hearing assembly, axial bulges of the pocket webs occur, which bulges can lead to the ball rollers jamming in their cage pockets and ultimately to malfunctions of the ball roller bearing. The low flexural stiffness of the pocket webs can likewise lead to high fluctuations in the cage deflection during hearing operation, as a result of which undesirable high bearing noise additionally occurs in conjunction with the sharp edges of the punched-out cage pockets.